Transformer



Dec. 4, 1923.

R. V. BINGAY TRANS'FORMER Filed Sept. 6. 1921 INVENTOR @W I g 4 @M ,L4 AT'roleNEm 21M ma, a

PatentedvDec. 4, 1923.

i UNITED STATES PATENT oFIilcE.

ROBERT V. BINGAY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 PITTSBURGHTRANSFORMER COMPANY, A CORPORATION OF PENNSYLVANIA.

TRANSFORMER.

Application led September 6, 1921.

T o allzu/1.0m t may concern.'

Be it known that I, ROBERT V. BINGAY, a citizen of the United States,residing at Pittsburgh, in lthe county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inTransformers, of which the following is a specification.

In electric transformers containing oil for insulating and coolingpurposes, it is customary not to completely fill the transformer tankwith the oil unless an expansion or overflow tank is provided, in whichcase the overfiow tank is not completely filled. Thus, in either casethere is present an air space above the oil. When the transformerbecomes heated the oil expands and it is customary to provide an outletin the upper part of the tank for the air to pass from the 4tank to theexternal atmosphere during the heating and expansion of the'oil. Whenthe transformer cools, the reverse operation takes place and outside airis drawn into the tank. This action results in a certain amount ofmoisture being carried into the air space of the tank and consequentlyto the oil with each cooling of the transformer. Even if care has beentaken to exclude all moisture from the oil and air space when thetransformer is assembled, it results that after continued useconsiderable moisture will be introduced by the action above described',unless special means is taken to prevent it. As moisture in oil causesits insulatin properties to deteriorate in accordance wlth the amount ofmoisture absorbed, it becomes important to prevent any accumulation ofmoisture or to reduce its presence to a minimum if the high insulatingquality of the oil is to be maintained.

Many devices have been resorted to for overcoming the above difficultybut have not proved satisfactory, either on account of thecumbersomeness of the auxiliary devices provided which are expensive andoccupy valuable space, or require regular attention on the part of theoperator.

The objectof my invention is 'to provide a device which will beeffective in operation, simple and durable in construction and occupy asmall amount of space, and at the same time require a minimum degree ofattention on the part of the operator, and which will operate to preventmoisture from entering the tank.

Serial No. 498,769.

My invention and its advantages will be understood from the followingdescription and accompanyin drawings.

Fig. l is a side e evation of a transformer embodying my invention, Fig.2 is a vertical central section of a portion of the auxiliaryattachment,and Flg. 3 is a modification of the device.

Fig. 1 shows one form of transformer to which my improvement is applied,but my invention may be applied to any form of transformer constructionwhich is provided with a tank for enclosing the transformer andcontaining an insulating fiuid with an air space above it. In Fig. 1 afluted tank A is illustrated which contains a transformer and has an airtight cover B. A manhole cover is indicated at C and the usualinsulators D are shown for insulating 'the leads which ass out throughthe cover.

At t e top `of the tank and preferably in the cover is a pipe connectionE with an air space. This pipe leads to a device F which contains a discG of filter paper which permits the passage of air, and prevents thepassaige of moisture, such as the filter paper ordinarily used forfiltering moisture out of oil. The device F may be of any suitable formfor carrying the disc G. In the form shown in Figs. 1 and 2 the couplingcomprises two oppositely disposed anges, f,If, between which is clampedfilter paper G. n the modification shown in Fig. 3, a standard couplingis shown having a part l which re ceives the pipe E. The part l isenlarged at its lower portion and has a threaded engagement with a part2 having an outwardly extending flange 2. A nut 3 has an inwardlyextendin flange 3 at its upper end which engages t e flange 2a. A part 4has a threaded engagement with the nut 3 and in turn is engaged at itslower end by a reducing cap or nut 5 and carries the pipe 6 at its lowerend. The disc G may obviously be easily inserted and removed.

In operation, when the transformer becomes heated and the oil levelrises, air'will be forced out through the pipe E and disc G. When thetransformer cools and the oil level decreases, air will be drawn inthrough the disc G and pipe E; but in passing out of the oil the dry airis afterwards expelled from the transformer through the disc G it willabsorb an moisture on the under surface or any moisture which may beabsorbed in the disc G and will thus thoroughly dry the disc so that itwill be in its most effective condition to prevent any moisture fromentering the transformer when it cools.

Thus my invention effectively protects the transformer from the entranceof moisture and the filtering disc G is self drying and in effectivecondition for4 excluding mois- 'ture from entering the transformer eachtime air is drawn in and through the disc.

In some instances several discs G may be used, one over the other andspaced apart from each other, the number of the discs used and theirspacing depending upon the capacity of the transformer and degree ofexpansion and contraction. The disc or discs may be reinforced' orsupported by wire gauze g, as shown in Fig. 2, if so desired.

The filter paper disks being fragile will puncture in the event of asudden increase in pressure in the transformer tank, such as might occurfrom arcing at the transformer, and in this manner provide a free ventfor the relief of excessive pressure Within the tank.

I claim 1. The combination with a transformer tank or the like,containing a fluid and having an enclosed space permitting the fluid toexpand and contract, of means4 for permitting the passage of air to andfrom said space comprising a material in the path of the inflowing airadapted to mechanically separate moisture therefrom so as to preventsaid moisture from entering said tank, said material being adapted toyield up moisture to dry air so as to be dried thereby. 2. Thecombination with a transformer tank or the like, containing' a Huid andhaving an enclosed space permitting the fluid to expand and contract, ofmeans for permitting the passage of air to and from said spacecomprising a material in the path of the inflowing air adapted tomechanically separate moisture therefrom so as to prevent said moisturefrom entering said tank, said material being adapted to yield upmoisture to dry air so as to be dried thereby, and assume a moistureexcluding condition on exposure to dry atmosphere.

3. The combination with a transformer tank or the like, containing afluid and having an enclosed space permitting the fiuid to expand andcontract, Aof means for permitting the passage of air to andfrom saidspace comprisin a. material inthe vpath of the inflowing air adapted tomechanically separate moisturev therefrom so as to prevent said moisturefrom enteringr said tank, said material being in the form of a diskthrough which the entering air passes.

4c., The combination of a `transformer tank or the like, containing afluid and having an enclosed space permitting the fiuidto expand andcontract, of means for permitting the passage of air to and from saidspace comprising a filter paper in the path of the inflowing air adaptedto mechani- Y cally filter out moisture therefrom so as to prevent saidmoisture from entering said tank.

5. The combination with a transformer tank or the like, containing afluid and having an enclosed space permitting the fiuidto expand andcontract, of means for permitting the passage of air to and from saidspace comprising a material in the path of the iniowin air adapted tomechanically separate moisture therefrom so as to prevent said moisturefrom entering said tank, the said material being exposed on one side tothe surrounding atmosphere. Y

6. The combination with an oil container forming an enclosed spaceadapted to contain air, means forming a passage for the flow of airbetween the said space and a body of air external to said container andmeans in the path of said flow of air for absorbing moisture from air.fiowing along said path in one direction and giving out moisture to airowing in the opposite direction.

7. The combinationA `with electrical" alp-l paratus, of a containertherefor forming an enclosed space adapted to contain air,

means forming a. passage for the flow of air between the said space anda body of air external to said container and means in the path of saidHow of air for absorbing moisture from air flowingalong'said path in onedirection and giving out moisture to air iiowing in the oppositedirection.

8. The combination with electrical apparatus, of a container thereforforming an enclosed space adapted to contain ain.

means forming a Aassage for the How of air between the said) space and abody of air external to said container, fibrous material extendingacross the path of said How of air for absorbing moisture from airfiowing along said path in one ,direction and giving out moisture to airowing in the opposite direction. d

9. The combination with electrical apparatus, of a container thereforforming an enclosed space adapted `to contain air, means forming apassagefor theiow of air between the said space and a body ofy airexternal to said container and fragile means in the path of said How ofair for absorbing moisture from air fiowing along said path in onedirection and giving out moisture to air flowing inthe oppositedire-ction.

ROBERT V. BINGAY.

